Question

The electronic configurations of three elements X, Y, and Z are $\text{X}—2,8$; $\text{Y}—2,8,7$ and $\text{Z}—2,8,2$. Which of the following is correct?

• A. X is a metal
• B. Y is a metal
• C. Z is a non-metal
• D. Y is a non-metal and Z is a metal

Answer 1

The correct option is D

Y is a non-metal and Z is a metal

Explanation for correct option

(D)Y is a non-metal and Z is a metal

Electronic configuration:

• “The distribution of electrons into orbitals of an atom is called its electronic configuration”.
• $\text{X}=1s^{2}2s^{2}2p^6=2,8=10$
• It is the electronic configuration of neon. It is a noble gas. It is a nonmetal.
• $\text{Y}=1s^{2}2s^{2}2p^{6}3s^{2}3p^5=2,8,7=17$
• It is the configuration of the chlorine atoms which is non-metal.
• $Z=1s^{2}2s^{2}2p^{6}3s^2=2,8,2=12$
• It is the configuration of alkaline earth metals of magnesium atom which is metal.
• So, Y is a non-metal, and Z is a metal.

Explanation for incorrect option

Y is a non-metal, and Z is a metal. Hence, options (A), (B), and (C) are incorrect.

Hence, option (D) is correct. Y is a non-metal, and Z is a metal.